Katsuma from Moshi Monsters does not have a specified age as it is a fictional character in a virtual pet game. The game does not provide specific ages for its characters, as they are designed to appeal to a wide range of ages and do not have fixed birthdates. Katsuma's age is simply part of the imaginative world of Moshi Monsters and is not meant to be interpreted in a literal sense.
You can decide for yourself whether your Katsuma is a boy or a girl. Moshi Monsters does not tell you the gender of your monster because they want you to use your imagination.
There are 6 different types of monsters on Moshi Monsters: Poppet Diavlo Zommer Katsuma Furi Luvli
The most common Katsuma colour is purple and green.
You can make your Moshi Monster either a boy or a girl so it does not really matter. Moshi Monsters does not tell you the gender!
For katsuma its MOSHI33 for furi its GOLDENFURI and diavlo is SHOTPUT